Gas turbine engine regenerator

ABSTRACT

A heat regenerator system for a gas turbine engine comprising a main turbine housing adapted to enclosed the power turbine wheel and the compressor drive wheel, a cylindrical regenerator core having axial gas flow passages mounted for rotation about a vertical axis in the upper region of the housing, a regenerator cover in the housing defining a high pressure regenerator inlet chamber in communication with the outlet side of the compressor, a generally circular lower seal surface formed in the housing in registry with a lower peripheral seal for the regenerator core, an arcuate enclosure formed within the housing for receiving a peripheral portion of the regenerator core and forming an upper regenerator core seal support surface surrounding the low pressure exhaust region for the regenerator core and an exhaust gas flow passage formed in the housing and adapted to receive low pressure exhaust gases directed by the regenerator cover from the regenerator core exhaust region.

United States Patent [191 Stockton Feb. 12, 1974 GAS TURBINE ENGINE REGENERATOR [75] Inventor: Thomas R. Stockton, Ann Arbor,

Mich.

[73] Assignee: Ford Motor Company, Dearborn,

Mich.

[22] Filed: June 19, 1972 [211 Appl. No.: 263,829

Primary Examiner-Carlton R. Croyle Assistant Examiner-Warren Olsen Attorney, Agent, or Firm-Donald J. Harrington; Keith L. Zerschling [57] ABSTRACT A heat regenerator system for a gas turbine engine comprising a main turbine housing adapted to enclosed the power turbine wheel and the compressor drive wheel, a cylindrical regenerator core having axial gas flow passages mounted for rotation about a vertical axis in the upper region of the housing, a regenerator cover in the housing defining a high pressure regenerator inlet chamber in communication with the outlet side of the compressor, a generally circular lower sea] surface formed in the housing in registry with a lower peripheral seal for the regenerator core, an arcuate enclosure formed within the housing for receiving a peripheral portion of the regenerator core and forming an upper regenerator core seal support surface surrounding the low pressure exhaust region for the regenerator core and an exhaust gas flow passage formed in the housing and adapted to receive low pressure exhaust gases directed by the regenerator cover from the regenerator core exhaust region.

6 Claims, 3 Drawing Figures PATENTEDFEB 12 I974 3791 138 sum 1 or 2 .17 izz% GAS TURBINE ENGINE REGENERATOR GENERAL DESCRIPTION OF THE INVENTION My invention relates generally to gas turbine engines for vehicles. A gas turbine engine presently used comprises a gas turbine housing that encloses the power turbine and compressor turbine sections, the compressor turbine being connected drivably to an air compressor which compresses inlet air and distributes it to a high pressure chamber or diffuser region on the inlet side of the turbine combustion chamber. A regenerator cover is used to direct the inlet air flow to the inlet flow region of a regenerator core which in turn is mounted for rotation about a vertical axis in the upper region of the housing. The cover is used also to conduct exhaust gases from the low pressure exhaust flow region of the regenerator core, which is formed in the cover. The exhaust region of the regenerator core receives thermal energy from the power turbine exhaust gases. As the core is rotated the thermal energy that is stored in it is transferred to the inlet air flow section of the regenerator thereby heating the high pressure inlet gases that are received by the combustion chamber.

In my improved regenerator system the regenerator core is received within a C-shaped closure in the portion of the housing within the low pressure exhaust gas region. The housing defines a pair of vertically spaced seal shoulders disposed on either side of the periphery of the generator core. Seal structures are provided on the upper and lower peripheral surfaces of the regenerator core in the exhaust gas flow region so that the high pressure inlet side of the regenerator is effectively sealed from the low pressure exhaust region. This sealing arrangement prevents high pressure gases from acting on the portion of the regenerator cover adjacent the exhaust flow region. The sealing gasket normally used for sealing the regenerator cover where it engages the housing then is not exposed to the high pressure that exists on the inlet side of the regenerator.

My improved engine also includes a regenerator cover that may be formed of thin sheet metal. Preferably it is fabricated by a stamping operation. Usually in turbine engines of the type used for vehicle power plants, the regenerator cover is a heavy casting that is cored to provide inlet flow passages and exhaust flow passages. The overall height of the engine is increased accordingly. In contrast, the simplified sheet metal regenerator cover of my improved assembly makes it possible to reduce the overall height of the engine since the exhaust porting for the exhaust gases is located in the main engine housing rather than in the cover. Complex machining or casting operations are not necessary to effect the necessary clearances and flow passages in the cover. Rigidity is achieved, notwithstanding the thin sheet metal construction of the cover, by providing a crossbar that is secured fast to the central portion of the cover. It extends generally diametrically across the regenerator core. The exposed surface of the crossbar forms one of the sealing surfaces for the seal that surrounds the regenerator core exhaust region.

BRIEF DESCRIPTION OF THE FIGURES OF THE DRAWING FIG. 1 shows in schematic isometric form a gas turbine engine main housing. FIG. 1 shows also a stamped sheet metal cover separated from the upper surface of the housing.

FIG. 2 is a cross sectional view taken along the vertical plane that includes the axis of rotation of the rotary turbine shaft for the engine.

FIG. 3 is a partial cross sectional view of a cross bar of FIG. 2 as seen from a plane of sectional line 3-3 of FIG. 2.

PARTICULAR DESCRIPTION OF THE INVENTION In FIG. 1 reference character 10 designates the main housing portion. It includes an air inlet opening 12 and an exhaust gas opening 14. It includes also inner walls 16 and 18 which define in part a chamber that receives combustion gases from the combustion chamber. Wall 16 separates the inlet flow chamber or diffuser chamber 20 from the combustion gas exhaust chamber. Diffuser chamber 20 receives compressed air from the centrifugal compressor which is driven by the compressor turbine section of the engine. The compressor is mounted within a housing which may be bolted to the outer surface 22 of the housing 10.

Wall 18 separates the combustion gas exhaust region on the intake side of the regenerator core from the combustion gas exhaust region on the outlet side of the regenerator core. The combustion gases passing through the regenerator core are directed by regenerator cover 24 to exhaust gas opening 26 which communicates with the exhaust port 14. A separator wall 28 is disposed between the chambers defined by walls 16 and 18. This effectively separates the exhaust gases passing from the power turbine section from the inlet air on the outlet side of the regenerator core flow intake region.

The regenerator core is best seen by referring to FIG. 2. It is identified by reference character 30. It comprises a cylindrical rigid matrix having axial flow passages, and it is mounted for rotation about axis 32. The periphery of the regenerator core is situated adjacent sealing surfaces 34 and 36 comprising a shelf formed at the upper extremity of the walls 16 and 18, respectively. A third sealing surface 38, which joins the surfaces 36 and 34, extends across the center of the regenerator core 30 in the same plane as the surfaces 34 and 36. A peripheral lower seal 40 registers with the lower peripheral surface of the regenerator core 30 and is seated on the surfaces 34 and 36. A crossover portion or cross-arm for the seal 40 is shown at 42. It registers with the sealing surface 38.

The low pressure exhaust flow region of the regenerator core 30 is received within enclosure 44 formed within the housing as part of an integral housing structure. The enclosure 44 is generally C-shaped and it surrounds the exhaust gas flow region of the regenerator core. Sealing surface 36 is located on the lower margin of the enclosure 44 and sealing surface 46 is located on its upper margin. Surface 46 is formed asa ledge which forms a part of the housing structure. A seal 48 surrounds the periphery of the low pressure exhaust region of the regenerator core, and it registers with the sealing surface 46.

A crossbar 50, as best seen in FIG. 1, extends across the enclosure 44. One end of the bar 50 is received within a pocket 52 formed in the upper housing surface 54. The other end registers with pocket 56 formed in the upper surface 54. Bar 50 bridges the enclosure 44 and its under-surface 58 defines a sealing surface for the so-called D-shaped seal 48. The arcuate portion of this seal 48 registers with a periphery of the regenerator core and with sealing surface 46. A straight portion of the D seal 48 registers with the sealing surface 58.

The upper surface 54 of the housing defines a single upper plane to which regenerator cover 60 is bolted. Cover 60 is formed with depressions 62 and 64 which define respectively a high pressure intake air receiving chamber and a low pressure exhaust gas receiving chamber. The cover 50 may be formed by stamping relatively thin sheet metal stock. A gasket 66 surrounds the cover 60 to provide a seal at the upper surface 54 of the housing.

The depression 64 conducts low pressure exhaust gases from the outlet side of the regenerator core to exhaust opening 26 formed in the housing 10. After they are collected in the opening 26 they are distributed to exhaust port 14.

In order to provide the desired stiffness of the cover 60, a crossbar 68 is bolted to the inner surface of the cover 60 as indicated best in FIGS. 1 and 2. A regenerator pivot bolt 70 is received through the cover and through the crossbar as indicated in FIG. 1. It is threaded and secured to the central wall 38 of the housing 10.

I have shown in FIG. 3 the assembly of the cover 60 and the crossbar 68. The upper surface of the crossbar is bolted to the central region of the cover 60. The ends of the crossbar are bolted, one bolt being shown at 72. Shims may be located, if necessary, between the upper surface of the pocket 52 and the registering surface of the ends of the crossbar 68 in order to provide flush alignment of the seal deck surfaces at each end of the crossbar.

The regenerator core is surrounded by a ring gear 74 which is engaged by a drive pinion. The pinion in turn is powered by means of a driving connection between the power turbine shaft and the drive pinion. The regenerator core rotates as the engine is driven thereby transferring thermal energy stored in the regenerator core exhaust gas region to the intake flow region where it results in an increase in temperature of the inlet gases. Typically the air temperature on the outlet side of the compressor and the inlet side of the regenerator core is about 450 F. The temperature of the exhaust gases at the exit of the power turbine section may be about 1,450 F. As the exhaust gases pass through the regenerator core, the temperature of the gases falls to approximately 525 F. Any distortion of the regenerator core due to these differential temperatures may be accommodated by the peripheral seals and by the seals that register with the crossbar 50 and the sealing surface 38 On the underside of the regenerator core.

The gasket on the low pressure side of the engine is not subjected to the high pressure that exists on the outlet side of the compressor because the high pressure side and the low pressure side are isolated, one from the other, by the regenerator core seals. Fewer holddown bolts for the cover then are necessary in comparison to the number of holddown bolts required for a conventional gas turbine engine regenerator cover.

Having thus described a preferred embodiment of my invention, what I claim and desire to secure by U.S. Letters Patent is:

l. A gas turbine engine comprising a turbine engine housing defining a high temperature gas receiving portion and a low temperature exhaust receiving portion, internal housing walls separating the housing portions, said housing portions being defined in part by internal walls having an upper regenerator sealing surface, said housing defining also an air intake chamber that is isolated from said housing portions, an arcuate enclosure formed in said housing at the upper region thereof, a rotary regenerator core journalled for rotation in the upper portion of said housing, said enclosure having ledge portions that overlie the periphery of said regenerator core in the region of the low temperature exhaust gases, a cover enclosing the upper portion of said housing and said regenerator core, an exhaust gas port formed in said housing, said cover being adapted to conduct inlet air from said inlet air chamber to the intake side of said regenerator core and to conduct exhaust gases from the outlet side of the regenerator core to said exhaust port.

2. The combination as set forth in claim 1 wherein said exhaust port communicates with the upper region of said housing and is in communication with the exhaust gas flow exit side of said regenerator core through said cover, and a gasket disposed between said cover and said housing, the portion of the gasket communicating with the exhaust flow gases being isolated from the high pressure intake portion of said regenerator core.

3. The combination as set forth in claim 1 wherein said cover includes a crossbar secured thereto and extending across its central portion, said crossbar having a lower sealing surface that is generally coplanar with the sealing surface formed about the margin of said arcuate enclosure in said housing and defining a sealing surface for the regenerator core seal on the outermost surface of said regenerator core.

4. The combination as set forth in claim 2 wherein said cover includes a crossbar secured thereto and extending across its central portion, said crossbar having a lower sealing surface that is generally coplanar with the sealing surface formed about the margin of said arcuate enclosure in said housing and defining a sealing surface for the regenerator core seal on the outermost surface of said regenerator core.

5. A gas turbine engine having a heat exchanger for transferring thermal energy from exhaust flow gas to turbine inlet air comprising a housing, said housing having a regenerator opening formed therein, a ledge extending around a portion of said opening, and projecting toward the center of said opening, an exit opening in said housing for accommodating exhaust gases leaving the engine, walls in said housing separating high pressure gases from low pressure gases in said engine, said walls having a shelf defining a sealing surface located a short distance below said opening in said housing, a rotary regenerator core rotatably mounted above said shelf with a portion of said core located between said shelf and said ledge, a cover fitted over said opening in said housing, and an exhaust port in said housing, said cover being adapted to transfer exhaust gases passing through said regenerator core to said exhaust port. pressure gases whereby rigidity of said cover is increased on the lower surface of said crossbar register- 6. The combination as set forth in claim 5 wherein said cover includes a crossbar attached at its ends to said housing over a portion of said internal wall struc- 5 an exhaust gas Porno of the regenerator coreture that divides said high pressure gases from said low ing with said regenerator seal portion which surrounds 

1. A gas turbine engine comprising a turbine engine housing defining a high temperature gas receiving portion and a low temperature exhaust receiving portion, internal housing walls separating the housing portions, said housing portions being defined in part by internal walls having an upper regenerator sealing surface, said housing defining also an air intake chamber that is isolated from said housing portions, an arcuate enclosure formed in said housing at the upper region thereof, a rotary regenerator core journalled for rotation in the upper portion of said housing, said enclosure having ledge portions that overlie the periphery of said regenerator core in the region of the low temperature exhaust gases, a cover enclosing the upper portion of said housing and said regenerator core, an exhaust gas port formed in said housing, said cover being adapted to conduct inlet air from said inlet air chamber to the intake side of said regenerator core and to conduct exhaust gases from the outlet side of the regenerator core to said exhaust port.
 2. The combination as set forth in claim 1 wherein said exhaust port communicates with the upper region of said housing and is in communication with the exhaust gas flow exit side of said regenerator core through said cover, and a gasket disposed between said cover and said housing, the portion of the gasket communicating with the exhaust flow gases being isolated from the high pressure intake portion of said regenerator core.
 3. The combination as set forth in claim 1 wherein said cover includes a crossbar secured thereto and extending across its central portion, said crossbar having a lower sealing surface that is generally coplanar with the sealing surface formed about the margin of said arcuate enclosure in said housing and defining a sealing surface for the regenerator core seal on the outermost surface of said regenerator core.
 4. The combination as set forth in claim 2 wherein said cover includes a crossbar secured thereto and extending across its central portion, said crossbar having a lower sealing surface that is generally coplanar with the sealing surface formed about the margin of said arcuate enclosure in said housing and defining a sealing surface for the regenerator core seal on the outermost surface of said regenerator core.
 5. A gas turbine engine having a heat exchanger for transferring thermal energy from exhaust flow gas to turbine inlet air comprising a housing, said housing having a regenerator opening formed therein, a ledge extending around a portion of said opening, and projecting toward the center of said opening, an exit opening in said housing for accommodating exhaust gases leaving the engine, walls in said housing separating high pressure gases from low pressure gases in said engine, said walls having a shelf defining a sealing surface located a short distance below said opening in said housing, a rotary regenerator core rotatably mounted above said shelf with a portion of said core located between said shelf and said ledge, a cover fitted over said opening in said housing, and an exhaust port in said housing, said cover being adapted to transfer exhaust gases passing through said regenerator core to said exhaust port.
 6. The combination as set forth in claim 5 wherein said cover includes a crossbar attached at its ends to said housing over a portion of said internal wall structure that divides said high pressure gases from said low pressure gases whereby rigidity of said cover is increased on the lower surface of said crossbar registering with said regenerator seal portion which surrounds an exhaust gas portion of the regenerator core. 